revlog: introduce a `display_id` property
We currently using the "index file" to identify a revlog in error output. Since
we are about to make the "index file" location more volatile, we need something
better. We move to use the "radix", as it is close to what we currently use.
We could probably do better, as pointed out in the comment, however that would
be a quite detour from my current goal.
Differential Revision: https://phab.mercurial-scm.org/D10579
#require no-icasefs
test file addition with colliding case
$ hg init repo1
$ cd repo1
$ echo a > a
$ echo A > A
$ hg add a
$ hg st
A a
? A
$ hg add --config ui.portablefilenames=abort A
abort: possible case-folding collision for A
[255]
$ hg st
A a
? A
$ hg add A
warning: possible case-folding collision for A
$ hg st
A A
A a
$ hg forget A
$ hg st
A a
? A
$ hg add --config ui.portablefilenames=no A
$ hg st
A A
A a
$ mkdir b
$ touch b/c b/D
$ hg add b
adding b/D
adding b/c
$ touch b/d b/C
$ hg add b/C
warning: possible case-folding collision for b/C
$ hg add b/d
warning: possible case-folding collision for b/d
$ touch b/a1 b/a2
$ hg add b
adding b/a1
adding b/a2
$ touch b/A2 b/a1.1
$ hg add b/a1.1 b/A2
warning: possible case-folding collision for b/A2
$ touch b/f b/F
$ hg add b/f b/F
warning: possible case-folding collision for b/f
$ touch g G
$ hg add g G
warning: possible case-folding collision for g
$ mkdir h H
$ touch h/x H/x
$ hg add h/x H/x
warning: possible case-folding collision for h/x
$ touch h/s H/s
$ hg add h/s
$ hg add H/s
warning: possible case-folding collision for H/s
case changing rename must not warn or abort
$ echo c > c
$ hg ci -qAmx
$ hg mv c C
$ cd ..